The proposed study will examine the feasibility, acceptability, safety, effectiveness, and cost of an Accessible Care intervention for engaging people who inject illicit drugs (PWID) in hepatitis C care. Four times as prevalent in the US as HIV infection, hepatitis C is already the leading cause of liver failure and liver transplantation, and the disease burden and health care costs will continue to rise in the coming decades. The 1.5-2.0 million PWID constitute the core of the hepatitis C epidemic in the United States, with prevalence rates >70% in most studies. New, all-oral antiviral treatment regimens can eradicate HCV in nearly 100% of previously untreated patients. Nonetheless, few studies have reported successful treatment of this infection in active PWID - none with the new all-oral regimens - and they are rarely offered antiviral treatment. As more advantaged populations gain access to the treatments and are cured, health disparities in hepatitis C outcomes will sharpen. Accessible Care for PWID is low-threshold care provided in programs designed specifically for PWID, in community-based locations where they can comfortably access care without fear of shame or stigma. The proposed study will compare the effectiveness of Accessible Care with Usual Care (referrals to existing services) in facilitating linkage, engagement, and retention of PWID in care for hepatitis C, addiction, and HIV prevention. Our primary outcome is sustained virologic response (SVR), which constitutes virologic cure. Substance use and HIV and HCV risk behaviors are secondary outcomes. The Specific Aims of this study are to compare active PWID receiving Accessible Care or Usual Care on the following outcomes: 1. Hepatitis C Outcomes: (1a) Linkage and engagement in hepatitis C care, (1b) Successful hepatitis C treatment, (1c) Safety of hepatitis C treatment, and (1d) Rates of reinfection. 2. Substance use outcomes: (2a) Substance abuse treatment entry and retention, and (2b) Reductions in substance use. 3. Reductions in self-reported HIV and HCV risk behaviors. As all-oral regimens become available to patients who do not inject drugs, the substantial health disparities in hepatitis C already evident will become worse, as the haves are cured and the have-nots are not. Data are needed on effective methods to provide successful antiviral therapy to the core population affected by the epidemic, persons who are currently using illicit drugs, so that they, too, may benefit. Treatment can also help end the HCV epidemic by preventing onward transmission - Treatment as Prevention - but only if we have effective models for delivering treatment to people actively injecting drugs.